Combining oxidative coupling and reforming of methane: vision or utopia?

Methane, which is the principal component of natural gas reserves, is currently being used for home and industrial heating and for the generation of electrical power. Methane is an ideal fuel because of its availability in most populated centres, its ease of purification and the fact that is has the largest heat of combustion compared to the amount of CO2 formed, among all hydrocarbons. On the other hand, methane is an under-utilised resource for chemicals and liquid fuels. Known resources of natural gas are enormous and rival those of liquid petroleum. Transportation problems with methane and the increasing oil price have led to world-wide efforts for directly converting methane into easy transportable value added products, such as ethylene (feedstock for petrochemicals), aromatics and liquid hydrocarbon fuels. The main goal of the work described in this thesis was the development of an auto thermal process, combining the exothermic oxidative coupling of methane and highly exothermic combustion (side)reactions with the endothermic processes of methane steam reforming and methane dry reforming. The desired products are ethylene and synthesis gas. Two concepts for the combined process of oxidative coupling and reforming of methane are proposed. Because of the high reforming activity of ethane and ethylene, contact between C2 hydrocarbons and the reforming catalyst should be avoided. One concept combines oxidative coupling and reforming in structured spherical catalyst particles, consisting of an outer layer of oxidative coupling catalyst and a core of a reforming catalyst. The second concept combines oxidative coupling and reforming in different reactor compartments, still facilitating heat exchange between both processes. After oxidative coupling, reactive separation of ethylene by alkylation with benzene is performed. The remaining mixture converted with reforming reactions to synthesis gas. The total process will convert methane, oxygen and benzene to synthesis gas and ethylbenzene.